Urea 'climate solution' may backfire

Moves to fertilise the ocean with nutrients to boost CO2-consuming phytoplankton and fish stocks has prompted calls for international controls on such experiments (/iStockphoto)

Plans by an Australian company to sink hundreds of tonnes of urea into the ocean to combat climate change may backfire and exacerbate global warming, critics say.

Sydney-based company Ocean Nourishment Corporation (ONC) is looking at using nitrogen-rich urea to boost the growth of CO2-absorbing phytoplankton.

The idea, says the company, is for this form of carbon sequestration to lock up carbon in the oceans for thousands of years.

It says that encouraging the growth of more phytoplankton could also boost fish stocks.

But a number of scientists and civil society groups are worried about the lack of independent oversight of such private exploration of 'ocean fertilisation', which they say could trigger environmental problems rather than solve them.

And it's using the research of Adjunct Professor Ian Jones at the University of Sydney's civil engineering department to do so.

Jones has conducted laboratory experiments to show that nitrogen is important in boosting the growth of phytoplankton in ocean samples.

ONC has taken the research out of the lab. It has just completed an experiment involving 1 tonne of nitrogen in the Sulu Sea off the Philippines, says managing director John Ridley.

The company is now discussing with the Philippines government plans to scale up the experiment to 1000 tonnes of nitrogen over the next year.

Ridley says the company is also talking to the Moroccan government about similar experiments in the Atlantic Ocean.Concerns

But scientists involved in publicly-funded basic research into the role of nutrients including iron in the oceans are worried about the commercial imperative behind the latest experiments.

"This latest development in the Sulu Sea has all of our community concerned, as there doesn't appear to be any published evidence of how urea fertilisation impacts ocean biology and ecology," says biogeochemist Dr Philip Boyd of New Zealand's National Institute of Water and Atmospheric Research, or NIWA.

Dr Cliff Law of NIWA and others say independent scientific experts should oversee research by a growing number of private companies developing ocean fertilisation.

"At the end of the day we're dealing with companies that want to make money out of carbon credits," he says.

Phytoplankton blooms, as seen here in green, can occur as a result of natural ocean upwellings (Image: NASA)

ONC says there is little publicly available material on the field experiments, partly because of the need to protect intellectual property.

It says the experiments are mimicking natural upwelling of nutrients that occur in productive ocean areas.

In a commercial plant this would involve using urea produced from natural gas to sequester 10 megatonnes of CO2 per year.

It also says each of its plants could provide 50 grams of marine protein per day for 38 million people.

Others say such moves could bring bad news as well as good.

Law says natural upwelling of nutrients can trigger toxic algal blooms and the release of nitrous oxide, a more powerful greenhouse gas than CO2.

Ridley says the company will use ships to monitor phytoplankton growth and concentrations of nitrogen will not be allowed to go high enough to cause algal blooms.

"If we step the scale of this up we can actually track it by satellite," he says.

Law is not impressed.

"That all sounds very neat," he says. "If only it was so easy."

Law says boosting phytoplankton for fish stocks will also keep carbon circulating in the ecosystem, which would therefore undermine any sequestration efforts.

In addition, he says one of the challenges to long-term sequestration is drawing the dead phytoplankton down deep into the ocean.

Law says experiments seeding the ocean with iron have shown hardly any plankton sink below 100 metres, which means any carbon in them would be re-released within months.

Even if the plankton appear to sink, he says currents can bring them up again quite quickly.

Law says verifying long-term ocean carbon sequestration is difficult and expensive and he wonders how ONC will do this.London meeting discusses issue

An international scientific group on ocean dumping, known as the London Convention, is understood to be discussing urea ocean fertilisation at a meeting in the UK this week.

Earlier this week a coalition of civil society groups urged the convention to stop urea experiments until their impacts had been properly assessed.

Earlier this year the convention cautioned against ocean fertilisation using iron.

Ridley of ONC says the convention only has jurisdiction over experiments carried out in the high seas.

Instead, he says ONC will focus on territorial waters so it can be involved in carbon credit schemes.